(1) Field of the Invention
The present invention relates to the field of digital circuits. More specifically, the present invention relates to programmable logic circuits.
(2) Description of the Related Art
Programmable logic circuits may be implemented to perform various logic functions. Very often, the implementation of complex logic functions require a large number of logic gates. Typically, these logic gates include NAND and NOR logic gates when using CMOS technology. The use of NAND gates is preferable to the use of NOR gates, as NOR gates may consume a larger amount of power and require more voltage than NAND gates.
The use of programmable logic circuits for resolving various logic combinations may be disadvantageous as these circuits utilize logic elements that once programmed to achieve specific functions remain dedicated for the respective specific functions. Since dedicated elements, caused by programming, may not be changed to achieve other functions, once programmed, conventional programmable logic circuits are limited in the number of applications that may be implemented by way thereof. Such conventional logic circuits are also disadvantageous in that they need to be custom logic designed.
It is desirable to provide a "universal logic gate" (ULG) that may be trained to function in different logic ways. It is desirable to provide a ULG that alone or in conjunction with other such ULGs and/or other logic gates may be trained to provide almost any combinatorial logic function. It is also desirable to provide a method and apparatus for realizing various logic combinations with a minimum number of logic gates.